Comment by powersnail

To be honest, I would expect most small open source projects to just vanish, because of the lack of discoverability. The users won't be able to test them easily, and probably won't be paying for the shipping of a tiny tool that they have not yet tried and don't know whether it's useful or not.

Large open source projects can survive, but I'd imagine it will lean much more towards being developed mainly singular organizations. Without the internet, we don't just lose contributors, but also a lot of testers. The feedback loop will probably shrink, such that the software is mainly based on the need of the organization itself, and the perhaps a selected few collaborators who are very involved.